A 67-year-oldman underwent lower anterior resection for rectal cancer andresection of liver metastatic tumor 5 years later. Seven years and 2 months after the initial surgery, a soft tissue mass was detected in the left diaphragm. Further retrospective review of CT scan images showedthat the diaphragmatic tumor was present just before the hepatectomy. Partial resection of the left diaphragm was performed, and no relapse has occurred since then for 2 years. Most cases of diaphragmatic metastasis are considered to arise from dissemination, but we considered this case as more likely to be hematogenous. When surgery is chosen to treat metastatic tumors of colorectal cancer, checking for other metastasis via preoperative imaging andperforming curative resection is important.